Author Archives: Jennifer Margaret Gessler

New Studies on Memory and Marijuana usage.

Research shows that marijuana use affects short term memory, but how does it also affect Long Term Memory. How are short and Long Term memories are related. STM holds a small amount of information for a short amount of time. STM is processed in one of two ways, maintenance rehearsal and elaborative rehearsal. Elaborative rehearsal works better when transferring memories into LTM. Elaborative rehearsal is when you relate the information in STM to information you already have stored in LTM. Elaborative rehearsal works because we are processing the information on a deeper level. So in order to form LTM we must first be able to form STMs. How does the use of marijuana affect this process?
According to International weekly journal of science the THC in marijuana weakens the connections, or synapses, between neurons in the hippocampus. The hippocampus is a structure in the Medial Temporal lobe that is crucial for forming new LTMs. This was shown in a case where a person’s hippocampus’ were removed from both sides of the brain to eliminate epileptic seizures but also eliminated their ability to form new LTMs. Smoking marijuana is not as drastic as removing the hippocampus but because the hippocampus contains a lot of THC receptors it does affect the ability to form new LTMs. By the weakening of the connections in the hippocampus memory function is slowed down or stopped in Short and long term memory while on the substance.
Although the memory process is slowed down while using marijuana until recently long term affects affecting memory had not been seen. A study was done on teens who were using marijuana on a daily basis. The people in the study had started using marijuana between the ages of 16 and 17 and used it daily for 3 years. At the time of the study they had been marijuana free for two years. These participants performed 18% worse on long-term memory tests than young adults who had never used cannabis on a long term daily basis. These same participants who scored 18% less also had abnormally shaped hippocampus’. This is one of the first studies to show that correlation between long term memory problems and abnormally shaped hippocampus.
Marijuana is shown now to affect both short and long term memory. Although studies are just starting to be completed and further studies are starting up all over the globe. It is exciting to see what more we can learn about ourselves and the world around us.
Smith, M. J., Cobia, D. J., Reilly, J. L., Gilman, J. M., Roberts, A. G., Alpert, K. I., Wang, L., Breiter, H. C. and Csernansky, J. G. (2015), Cannabis-related episodic memory deficits and hippocampal morphological differences in healthy individuals and schizophrenia subjects. Hippocampus, 25: 1042–1051. doi: 10.1002/hipo.22427

HOW DOES MARIJUANA AFFECT THE BRAIN? (n.d.). Retrieved December 1, 2015, from
(n.d.). Retrieved December 1, 2015, from

Studies in False Memories is changing the criminal justice system

The study of False Memories is changing the criminal justice system. This new research shows how innocent adult participants were convinced and confessed to committing crimes as serious as assault with a weapon. The percentages were high, 71% developed a false memory of the crime, 50% of those false memories were elaborate in detail and their exact dealings with the police. This is big news by recognizing the procedures that generate these false memories allows the development of new procedures that support putting only criminals away.

Some of the first studies on false memories were done by Ira Hyman and coworkers in 1995. This study was done with college students and tested their memory of childhood events. This study showed that 20% recalled some detail of this false memory. This ability to create false memories is made stronger by certain factors. One of these factors is Priming, as seen in Stephen Lindsay’s experiment in 2004 showing participants an early childhood photo doubled the false memory recall.

The participants of the study done at the University of British Columbia study were 60 students that had never been involved in any of the crimes designated as a target for false memory. Each of these students participated in three 40-minute interviews that were a week apart. Priming starts in the first interview where the researcher told the student about two events experienced as a teen and only 1 of the 2 were true. The incidents were either related to crime and contact with police or emotional and personal in nature. The false event also included details that were taken from a true experience.

In the 2nd and 3rd interviews researchers continued to asks the participants to recall details of the event. When the memories seemed difficult to produce the researchers used statements such as “It is normal not to remember traumatic experiences” and included statements such as “Your parents have informed us that you did the crime” By triggering an emotional response the participants were able to take on the memory as their own and give details for an experience that never happened. Here we see Errors Due to Suggestion that is heighten because of priming and emotion. We also see Errors Due to Familiarity, by including familiar pieces of true early events in their lives.

This research from the University of British Columbia clearly shows that Police interrogation techniques can create false memories and opens the door for wrong fully convicted criminals to be vindicated. This creates a space for change in a system that drastically can alter someone’s life. By showing that certain techniques are bad is the first step in preventing them from happening.

West, R. (2015, November 19). Police interrogation tactics can plant false memories, UBC study finds – British Columbia – CBC News. Retrieved November 22, 2015, from

Goldstein, E. (2011). Everyday Memory and Memory Errors. In Cognitive psychology: Connecting mind, research, and everyday experience (3rd ed., pp. 225-233). Australia: Wadsworth Cengage Learning.

Shaw, J., & Porter, S. (2015). Constructing Rich False Memories of Committing Crime. Psychological Science, 291-301. Retrieved November 22, 2015, from

Visual Perception: Is Top down processing affected by Mood and emotions?

Visual Perception: Top down processing affected by Mood and emotions?

Is Visual Perception purely a top down process or do other factors alter our visual perception? Top down processing depends on a person’s prior knowledge or expectations. Bottom down processing begins with stimulation of the receptors. As someone living with mild depression, I know that emotions and mood can alter our perception. I believe our mood can alter how we see the world and what we get out of it. An experiment done in 2011 by Jacob Jolif and Maaike Meurs, University of Groningen, tested if how we feel changes how we perceive the world.

In top down processing perception is determined by three sources. These three sources are: stimulation of receptors (bottom-up processing), context in which the object appears, and knowledge or expectations of the perceiver. The idea that perception depends on knowledge was proposed in a theory back in the 19th century by physicist and physiologist Hermann von Helmholtz. Helmholtz’s Theory of Unconscious inference states that some of our perceptions are the result of unconscious assumptions that we make about the environment. What affect does mood and emotions further have on our perception?

The experiment conducted by Jolij and Meurs tested 43 students and analyzed the results. The task of each participant was to identify weather a happy face, sad face, or no face was seen after each trial. The trial was tested in 3 different scenarios to measure how mood affected the results. Each participant has 15 minutes of songs that made them feel happy and minutes that made them feel sad. Each scenario lasted 10 minutes at most and the music played through out. The participants all took the Self-Assessment Manakin in the beginning before either scenario was tested.

The experiment not only tested if mood affected visual stimulus but it also demonstrated how closely music and mood are interrelated. We all have experienced a song bringing a smile to our faces or possibly bringing on tears that we were not expecting. Participants of this experiment reported a significantly more positive mood with positive music, as compared to with no music and a more negative mood after listening to negative music.

The results of the experiment regarding visual perception show an elevation in detecting the correct face when music was present versus no music. During Happy music the participants were more accurate when it was a happy face and during sad music were more accurate when it was a sad face. The experiment proves the theory it was testing, that perception can be altered by your mood or emotions. It altered certain participant’s perception in such a way that they reported seeing happy or sad faces when no faces were present. The one aspect the experiment failed to acknowledge is the likelihood principle. The likelihood principle state that we perceive the object that is most likely to have caused the pattern of stimuli we have received. It’s likely that the participants saw faces correlating to the music they were listing due to the likelihood principle.

What part of the perception equation does mood and emotions affect? Could it be feedback signals are affected by emotions or mood? Feedback signals are associated with a person’s knowledge and expectations and are transmitted from higher levels of the brain then the receptors. It is certain that perception is more than top or bottom down processing.


Goldstein, E.B., (2001).Cognitive Psychology: Connecting Mind, research, and Everyday Experience, Canada, Linda Schreiber-Ganster

Jolij, J. & Meurs, M. (2011). Music Alters Visual Perception. Retrieved from